Techniques for enhanced machine type communication acknowledgment bundling

ABSTRACT

Techniques and apparatus for hybrid automatic retransmission request (HARQ) acknowledgement (ACK) bundling in half duplex frequency division duplexing (HD-FDD) systems are provided. One technique includes determining ACK parameter(s) to be used for acknowledging a bundled transmission that includes instance(s) of a channel across subframe(s). An indication of the ACK parameter(s) is signaled to a user equipment (UE). The ACK parameter(s) include a first ACK parameter that conveys a size of the bundled transmission and a second ACK parameter that conveys an amount of time for the UE to delay acknowledging a data transmission in an instance of the channel after receiving the data transmission. The UE may acknowledge the bundled transmission in accordance with the ACK parameter(s).

CROSS-REFERENCE TO RELATED APPLICATION & PRIORITY CLAIM

This application claims the benefit of and priority to IndianProvisional Patent Application Serial No. 201741004051, filed Feb. 3,2017, which is assigned to the assignee hereof and hereby expresslyincorporated by reference herein as if fully set forth below and for allapplicable purposes.

TECHNICAL FIELD

Certain aspects of the present disclosure generally relate to wirelesscommunications, and more particularly, to techniques for enabling hybridautomatic retransmission request (HARQ) acknowledgment (ACK) bundling incommunication systems, such as enhanced machine type communication(eMTC), that support half duplex (HD) operation (e.g., HD FrequencyDivision Duplexing (HD-FDD)).

INTRODUCTION

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access technologies includecode division multiple access (CDMA) systems, time division multipleaccess (TDMA) systems, frequency division multiple access (FDMA)systems, orthogonal frequency division multiple access (OFDMA) systems,single-carrier frequency divisional multiple access (SC-FDMA) systems,time division synchronous code division multiple access (TD-SCDMA)systems, and Long Term Evolution (LTE). LTE/LTE-Advanced is a set ofenhancements to the Universal Mobile Telecommunications System (UMTS)mobile standard promulgated by Third Generation Partnership Project(3GPP).

Generally, a wireless multiple-access communication system cansimultaneously support communication for multiple wireless terminals.Each terminal communicates with one or more base stations viatransmissions on the forward and reverse links. The forward link (ordownlink) refers to the communication link from the base stations to theterminals, and the reverse link (or uplink) refers to the communicationlink from the terminals to the base stations. This communication linkmay be established via a single-input single-output, multiple-inputsingle-output or a multiple-input multiple-output (MIMO) system.

A wireless communication network may include a number of base stationsthat can support communication for a number of wireless devices.Wireless devices may include user equipments (UEs). Machine typecommunications (MTC) may refer to communication involving at least oneremote device on at least one end of the communication and may includeforms of data communication that involve one or more entities that donot necessarily need human interaction. MTC UEs may include UEs that arecapable of MTC communications with MTC servers and/or other MTC devicesthrough Public Land Mobile Networks (PLMN), for example. In general, MTCdevices may include a broad class of devices in wireless communicationsincluding, but not limited to: Internet of Things (IoT) devices,Internet of Everything (IoE) devices, wearable devices and low costdevices.

To enhance coverage of certain devices, such as MTC devices, “bundling”may be utilized in which certain transmissions are sent as a bundle oftransmissions, for example, with the same information transmitted overmultiple subframes.

Multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of an emergingtelecommunication standard is new radio (NR), for example, 5G radioaccess. NR is a set of enhancements to the LTE mobile standardpromulgated by 3GPP. It is designed to better support mobile broadbandInternet access by improving spectral efficiency, lowering costs,improving services, making use of new spectrum, and better integratingwith other open standards using OFDMA with a cyclic prefix (CP) on thedownlink (DL) and on the uplink (UL) as well as supporting beamforming,multiple-input multiple-output (MIMO) antenna technology, and carrieraggregation. However, as the demand for mobile broadband accesscontinues to increase, there exists a need for further improvements inLTE, NR, and 5G technologies. Preferably, these improvements should beapplicable to other multi-access technologies and the telecommunicationstandards that employ these technologies.

BRIEF SUMMARY OF SOME EXAMPLES

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “DETAILED DESCRIPTION” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects of the present disclosure provide a method for wirelesscommunications that may be performed, for example, by a base station(BS). The method generally includes determining one or moreacknowledgment (ACK) parameters to be used for acknowledging atransmission that includes one or more instances of a channel across oneor more subframes. The method also includes signaling an indication ofthe one or more ACK parameters to a user equipment (UE). The one or moreACK parameters include a first ACK parameter that conveys a size of thetransmission and a second ACK parameter that conveys an amount of timefor the UE to delay acknowledging a data transmission in an instance ofthe channel after receiving the data transmission.

Certain aspects of the present disclosure provide an apparatus forwireless communication. The apparatus generally includes means fordetermining one or more acknowledgment (ACK) parameters to be used foracknowledging a transmission that includes one or more instances of achannel across one or more subframes. The apparatus also includes meansfor signaling an indication of the one or more ACK parameters to a userequipment (UE). The one or more ACK parameters include a first ACKparameter that conveys a size of the transmission and a second ACKparameter that conveys an amount of time for the UE to delayacknowledging a data transmission in an instance of the channel afterreceiving the data transmission.

Certain aspects of the present disclosure provide an apparatus forwireless communication. The apparatus generally includes at least oneprocessor and a memory coupled to the at least one processor. The atleast one processor is configured to determine one or moreacknowledgment (ACK) parameters to be used for acknowledging atransmission that includes one or more instances of a channel across oneor more subframes. The at least one processor is also configured tosignal an indication of the one or more ACK parameters to a userequipment (UE). The one or more ACK parameters include a first ACKparameter that conveys a size of the transmission and a second ACKparameter that conveys an amount of time for the UE to delayacknowledging a data transmission in an instance of the channel afterreceiving the data transmission.

Certain aspects of the present disclosure provide a computer-readablemedium having computer executable code stored thereon for wirelesscommunication by an apparatus. The computer executable code generallyincludes code for determining one or more acknowledgment (ACK)parameters to be used for acknowledging a transmission that includes oneor more instances of a channel across one or more subframes. Thecomputer executable code also includes code for signaling an indicationof the one or more ACK parameters to a user equipment (UE). The one ormore ACK parameters include a first ACK parameter that conveys a size ofthe transmission and a second ACK parameter that conveys an amount oftime for the UE to delay acknowledging a data transmission in aninstance of the channel after receiving the data transmission.

Certain aspects of the present disclosure provide a method for wirelesscommunications that may be performed, for example, by a user equipment(UE). The method generally includes receiving an indication of one ormore acknowledgement (ACK) parameters to use for acknowledging atransmission that includes one or more instances of a channel across oneor more subframes. The one or more ACK parameters include a first ACKparameter that conveys a size of the transmission and a second ACKparameter that conveys an amount of time for the UE to delayacknowledging a data transmission in an instance of the channel afterreceiving the data transmission. The method also includes acknowledgingthe transmission in accordance with the one or more ACK parameters.

Certain aspects of the present disclosure provide an apparatus forwireless communication. The apparatus generally includes means forreceiving an indication of one or more acknowledgement (ACK) parametersto use for acknowledging a transmission that includes one or moreinstances of a channel across one or more subframes. The one or more ACKparameters include a first ACK parameter that conveys a size of thetransmission and a second ACK parameter that conveys an amount of timefor the apparatus to delay acknowledging a data transmission in aninstance of the channel after receiving the data transmission. Theapparatus also includes means for acknowledging the transmission inaccordance with the one or more ACK parameters.

Certain aspects of the present disclosure provide an apparatus forwireless communication. The apparatus generally includes at least oneprocessor and a memory coupled to the at least one processor. The atleast one processor is configured to receive an indication of one ormore acknowledgement (ACK) parameters to use for acknowledging atransmission that includes one or more instances of a channel across oneor more subframes. The one or more ACK parameters include a first ACKparameter that conveys a size of the transmission and a second ACKparameter that conveys an amount of time for the apparatus to delayacknowledging a data transmission in an instance of the channel afterreceiving the data transmission. The at least one processor is alsoconfigured to acknowledge the transmission in accordance with the one ormore ACK parameters.

Certain aspects of the present disclosure provide a computer-readablemedium having computer executable code stored thereon for wirelesscommunication by an apparatus. The computer executable code generallyincludes code for receiving an indication of one or more acknowledgement(ACK) parameters to use for acknowledging a transmission that includesone or more instances of a channel across one or more subframes. The oneor more ACK parameters include a first ACK parameter that conveys a sizeof the transmission and a second ACK parameter that conveys an amount oftime for the apparatus to delay acknowledging a data transmission in aninstance of the channel after receiving the data transmission. Thecomputer executable code also includes code for acknowledging thetransmission in accordance with the one or more ACK parameters.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. The appended drawingsillustrate only certain typical aspects of this disclosure, however, andare therefore not to be considered limiting of its scope, for thedescription may admit to other equally effective aspects.

FIG. 1 is a block diagram conceptually illustrating an example of awireless communication network, in accordance with certain aspects ofthe present disclosure.

FIG. 2 shows a block diagram conceptually illustrating an example of abase station in communication with a user equipment (UE) in a wirelesscommunications network, in accordance with certain aspects of thepresent disclosure.

FIG. 3 is a block diagram conceptually illustrating an example of aframe structure in a wireless communications network, in accordance withcertain aspects of the present disclosure.

FIG. 4 is a block diagram conceptually illustrating exemplary subframeformats with the normal cyclic prefix, in accordance with certainaspects of the present disclosure.

FIGS. 5A and 5B illustrate an example of MTC co-existence within awideband system, such as LTE, in accordance with certain aspects of thepresent disclosure.

FIG. 6 illustrates an example logical architecture of a distributedradio access network (RAN), in accordance with certain aspects of thepresent disclosure.

FIG. 7 illustrates an example physical architecture of a distributedRAN, in accordance with certain aspects of the present disclosure.

FIG. 8 is a diagram illustrating an example of a downlink (DL)-centricsubframe, in accordance with certain aspects of the present disclosure.

FIG. 9 is a diagram illustrating an example of an uplink (UL)-centricsubframe, in accordance with certain aspects of the present disclosure.

FIG. 10 is a flow diagram illustrating operations performed by a BS, inaccordance with certain aspects of the present disclosure.

FIG. 11 is a flow diagram illustrating operations performed by a UE, inaccordance with certain aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in one aspectmay be beneficially utilized on other aspects without specificrecitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide techniques and apparatus forenabling hybrid automatic retransmission request (HARQ) acknowledgement(ACK) bundling in communication systems that support half duplexfrequency division duplexing (HD-FDD), e.g., such as systems thatsupport eMTC.

Some systems (e.g., eMTC) may include UEs (e.g., eMTC UEs) that arebandwidth reduced low complexity (BL) or coverage enhancement (CE)devices. Compared to non BL/CE devices, BL/CE devices may have one ormore reduced capabilities, examples of which may include, but are notlimited to, a reduction in maximum bandwidth, reduction of peak datarate, reduction of transmit power, HD operation, etc. Due in part tosuch limited capabilities, these devices may operate in one or more CEmodes, where each mode may support one or more different levels ofcoverage enhancement. In order to achieve coverage enhancement, multiplerepetitions/instances (e.g., bundling) of a same message (e.g., channel)may be transmitted over one or more subframes. Bundling, however, canaffect the timing across subframes, which in turn can impactcommunications (e.g., reduce the peak data rate) for eMTC UEs.Accordingly, it may be desirable to provide an efficient HARQ ACKbundling design to maximize the data throughput for eMTC UEs.

Aspects presented herein provide HARQ ACK bundling techniques that cansignificantly improve the peak data rate (e.g., DL throughput) for UEs(e.g., such as eMTC UEs) by enabling devices to dynamically adjust thetimeline relationship between bundled transmissions and HARQ feedbackassociated with the bundled transmissions. For example, a BS maydetermine one or more ACK parameters to be used (e.g., by a UE) foracknowledging a bundled transmission. The determination of the ACKparameter(s) may be based on one or more criteria, such as atype/capability of the UE (e.g., whether the UE is a eMTC UE), a CEmode, CE range/level, etc. The bundled transmission may include one ormore instances of a channel (e.g., physical downlink shared channel(PDSCH), machine type communication physical downlink control channel(MPDCCH), etc.) across one or more subframes. The ACK parameters mayinclude at least one of a delay parameter, bundle size parameter (e.g.,number of instances of the channel in the bundled transmission), whetherthe channel is transmitted in a last instance of the instances of thechannel, downlink assignment counter (DAD, etc.

Once the ACK parameter(s) are determined, the BS may signal the one ormore ACK parameters to a UE. The ACK parameter(s) can be used foracknowledging a bundled transmission from the BS or from another BS.Once the UE receives a bundled transmission, the UE may acknowledge thebundled transmission in accordance with the ACK parameters. In oneaspect, for example, the UE may determine the ACK parameters for eachinstance of the channel in the bundled transmission such that the UEtransmits an ACK (for all the instances) in the same uplink subframe.The ACK parameter(s) can maximize the peak data rate for the UE byenabling the UE to provide HARQ-ACK feedback (for a bundled transmissionacross multiple subframes) in a single uplink subframe.

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based on theteachings herein one skilled in the art should appreciate that the scopeof the disclosure is intended to cover any aspect of the disclosuredisclosed herein, whether implemented independently of or combined withany other aspect of the disclosure. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspect. Several aspects of telecommunication systems will now bepresented with reference to various apparatus and methods. Theseapparatus and methods will be described in the following detaileddescription and illustrated in the accompanying drawings by variousblocks, modules, components, circuits, steps, processes, algorithms,etc. (collectively referred to as “elements”). These elements may beimplemented using hardware, software, or combinations thereof. Whethersuch elements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

An access point (“AP”) may comprise, be implemented as, or known asNodeB, Radio Network Controller (“RNC”), eNodeB (eNB), Base StationController (“BSC”), Base Transceiver Station (“BTS”), Base Station(“BS”), Transceiver Function (“TF”), Radio Router, Radio Transceiver,Basic Service Set (“BSS”), Extended Service Set (“ESS”), Radio BaseStation (“RBS”), Node B (NB), gNB, 5G NB, NR BS, Transmit Receive Point(TRP), or some other terminology.

An access terminal (“AT”) may comprise, be implemented as, or be knownas an access terminal, a subscriber station, a subscriber unit, a mobilestation, a remote station, a remote terminal, a user terminal, a useragent, a user device, user equipment (UE), a user station, a wirelessnode, or some other terminology. In some implementations, an accessterminal may comprise a cellular telephone, a smart phone, a cordlesstelephone, a Session Initiation Protocol (“SIP”) phone, a wireless localloop (“WLL”) station, a personal digital assistant (“PDA”), a tablet, anetbook, a smartbook, an ultrabook, a handheld device having wirelessconnection capability, a Station (“STA”), or some other suitableprocessing device connected to a wireless modem. Accordingly, one ormore aspects taught herein may be incorporated into a phone (e.g., acellular phone, a smart phone), a computer (e.g., a desktop), a portablecommunication device, a portable computing device (e.g., a laptop, apersonal data assistant, a tablet, a netbook, a smartbook, anultrabook), wearable device (e.g., smart watch, smart glasses, smartbracelet, smart wristband, smart ring, smart clothing, etc.), medicaldevices or equipment, biometric sensors/devices, an entertainment device(e.g., music device, video device, satellite radio, gaming device,etc.), a vehicular component or sensor, smart meters/sensors, industrialmanufacturing equipment, a global positioning system device, or anyother suitable device that is configured to communicate via a wirelessor wired medium. In some aspects, the node is a wireless node. Awireless node may provide, for example, connectivity for or to a network(e.g., a wide area network such as the Internet or a cellular network)via a wired or wireless communication link. Some UEs may be consideredmachine-type communication (MTC) UEs or evolved MTC (eMTC) devices. MTCand eMTC UEs include, for example, robots, drones, remote devices,sensors, meters, monitors, location tags, etc., that may communicatewith a BS, another device (e.g., remote device), or some other entity.MTC devices and/or eMTC devices, as well as other types of devices, mayinclude Internet of Everything (IoE) or Internet of Things (IoT)devices, such as NB-IoT devices, and techniques disclosed herein may beapplied to MTC devices, eMTC devices, NB-IoT devices, as well as otherdevices.

It is noted that while aspects may be described herein using terminologycommonly associated with 3G and/or 4G wireless technologies, aspects ofthe present disclosure can be applied in other generation-basedcommunication systems, such as 5G and later, including NR technologies.

While aspects and embodiments are described in this application byillustration to some examples, those skilled in the art will understandthat additional implementations and use cases may come about in manydifferent arrangements and scenarios. Innovations described herein maybe implemented across many differing platform types, devices, systems,shapes, sizes, packaging arrangements. For example, embodiments and/oruses may come about via integrated chip embodiments and othernon-module-component based devices (e.g., end-user devices, vehicles,communication devices, computing devices, industrial equipment,retail/purchasing devices, medical devices, AI-enabled devices, etc.).While some examples may or may not be specifically directed to use casesor applications, a wide assortment of applicability of describedinnovations may occur. Implementations may range a spectrum fromchip-level or modular components to non-modular, non-chip-levelimplementations and further to aggregate, distributed, or OEM devices orsystems incorporating one or more aspects of the described innovations.In some practical settings, devices incorporating described aspects andfeatures may also necessarily include additional components and featuresfor implementation and practice of claimed and described embodiments.For example, transmission and reception of wireless signals necessarilyincludes a number of components for analog and digital purposes (e.g.,hardware components including antenna, RF-chains, power amplifiers,modulators, buffer, processor(s), interleaver, adders/summers, etc.). Itis intended that innovations described herein may be practiced in a widevariety of devices, chip-level components, systems, distributedarrangements, end-user devices, etc. of varying sizes, shapes, andconstitution.

An Example Wireless Communication System

FIG. 1 is a diagram illustrating a wireless network 100 in which aspectsof the present disclosure may be practiced. In aspects, as opposed tosending HARQ feedback separately for each transmission, techniquespresented herein can enable a UE to provide HARQ feedback for a bundledtransmission (e.g., a transmission of one or more instances of a channelacross one or more subframes), which in turn can maximize the peak datafor UEs. For example, the BS 110 may determine one or more ACKparameters to be used by UE 120 for acknowledging a bundled transmissionfrom the BS 110 or another BS 110, and signal the ACK parameters to theUE 120. The UE 120, in turn, may acknowledge a bundled transmissionreceived from the BS 110 (or another BS 110) in accordance with the ACKparameters. Doing so in this manner can maximize the DL throughput forUE(s) 120 (e.g., by allowing for additional subframes within a radioframe for downlink data).

The wireless network 100 may be an LTE network or some other wirelessnetwork, such as a NR or 5G network, and/or may support NB-IoT, MTC,eMTC, etc. Wireless network 100 may include a number of BSs 110 andother network entities. A BS is an entity that communicates with userequipments (UEs) and may also be referred to as a base station, eNB, aNR BS, a Node B, a gNB, a 5G NB, an access point, a TRP, etc. Each BSmay provide communication coverage for a particular geographic area. In3GPP, the term “cell” can refer to a coverage area of a BS and/or a BSsubsystem serving this coverage area, depending on the context in whichthe term is used.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). A BS for a macro cell may bereferred to as a macro BS. A BS for a pico cell may be referred to as apico BS. ABS for a femto cell may be referred to as a femto BS or a homeBS. In the example shown in FIG. 1, a BS 110 a may be a macro BS for amacro cell 102 a, an BS 110 b may be a pico BS for a pico cell 102 b,and a BS 110 c may be a femto BS for a femto cell 102 c. A BS maysupport one or multiple (e.g., three) cells. The terms “eNB”, “basestation”, “NR BS”, “gNB”, “TRP”, “AP”, “node B”, “5G NB”, and “cell” maybe used interchangeably herein.

In some examples, a cell may not necessarily be stationary, and thegeographic area of the cell may move according to the location of amobile base station. In some examples, the base stations may beinterconnected to one another and/or to one or more other base stationsor network nodes (not shown) in the access network 100 through varioustypes of backhaul interfaces such as a direct physical connection, avirtual network, or the like using any suitable transport network.

Wireless network 100 may also include relay stations. A relay station isan entity that can receive a transmission of data from an upstreamstation (e.g., a BS or a UE) and send a transmission of the data to adownstream station (e.g., a UE or a BS). A relay station may also be aUE that can relay transmissions for other UEs. In the example shown inFIG. 1, a relay station 110 d may communicate with macro BS 110 a and aUE 120 d in order to facilitate communication between BS 110 a and UE120 d. A relay station may also be referred to as a relay BS, a relaybase station, a relay, etc.

Wireless network 100 may be a heterogeneous network that includes BSs ofdifferent types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.These different types of BSs may have different transmit power levels,different coverage areas, and different impact on interference inwireless network 100. For example, macro BSs may have a high transmitpower level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relayBSs may have lower transmit power levels (e.g., 0.1 to 2 Watts).

A network controller 130 may couple to a set of BSs and may providecoordination and control for these BSs. Network controller 130 maycommunicate with the BSs via a backhaul. The BSs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wirelessnetwork 100, and each UE may be stationary or mobile. A UE may also bereferred to as an access terminal, a terminal, a mobile station, asubscriber unit, a station, etc. A UE may be a cellular phone (e.g., asmart phone), a personal digital assistant (PDA), a wireless modem, awireless communication device, a handheld device, a laptop computer, acordless phone, a wireless local loop (WLL) station, a tablet, a camera,a gaming device, a netbook, a smartbook, an ultrabook, medical device orequipment, biometric sensors/devices, wearable devices (smart watches,smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g.,smart ring, smart bracelet)), an entertainment device (e.g., a music orvideo device, or a satellite radio), a vehicular component or sensor,smart meters/sensors, industrial manufacturing equipment, a globalpositioning system device, or any other suitable device that isconfigured to communicate via a wireless or wired medium. Some UEs maybe considered evolved or enhanced machine-type communication (eMTC) UEs.MTC and eMTC UEs include, for example, robots, drones, remote devices,such as sensors, meters, monitors, location tags, etc., that maycommunicate with a base station, another device (e.g., remote device),or some other entity. A wireless node may provide, for example,connectivity for or to a network (e.g., a wide area network such asInternet or a cellular network) via a wired or wireless communicationlink. Some UEs may be considered Internet-of-Things (IoT) devices. SomeUEs may be considered a Customer Premises Equipment (CPE).

In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving BS, which is a BS designated toserve the UE on the downlink and/or uplink. A dashed line with doublearrows indicates potentially interfering transmissions between a UE anda BS.

One or more UEs 120 in the wireless communication network 100 (e.g., anLTE network) may also be a narrowband bandwidth UE. These UEs mayco-exist with legacy and/or advanced UEs (e.g., capable of operating ona wider bandwidth) in the LTE network and may have one or morecapabilities that are limited when compared to the other UEs in thewireless network. For example, when compared to legacy and/or advancedUEs in the LTE network, the narrowband UEs may operate with one or moreof the following: a reduction in maximum bandwidth (relative to legacyUEs), a single receive radio frequency (RF) chain, reduction of peakrate (e.g., a maximum of 1000 bits for a transport block size (TBS) maybe supported), reduction of transmit power, rank 1 transmission, halfduplex operation (e.g., HD-FDD), etc. In some cases, if half duplexoperation is supported, the narrowband UEs may have a relaxed switchingtiming from transmit to receive (or from receive to transmit)operations. For example, in one case, compared to a switching timing of20 microseconds (us) for legacy and/or advanced UEs, the narrowband UEsmay have a relaxed switching timing of 1 millisecond (ms).

In some cases, the narrowband UEs (e.g., in LTE Rel-12) may also be ableto monitor downlink (DL) control channels in the same away as legacyand/or advanced UEs in the LTE network monitor DL control channels.Release 12 narrowband UEs may still monitor downlink (DL) controlchannels in the same way as regular UEs, for example, monitoring forwideband control channels in the first few symbols (e.g., physicaldownlink control channel (PDCCH)) as well as narrowband control channelsoccupying a relatively narrowband, but spanning a length of a subframe(e.g., enhanced PDCCH (ePDCCH)).

Narrowband UEs may be limited to a particular narrowband assignment, forexample, of 1.4 MHz or six resource blocks (RBs) partitioned out of theavailable system bandwidth) while co-existing within a wider systembandwidth (e.g., at 1.4/3/5/10/15/20 MHz). Additionally, narrowband UEsmay also be able to support one or more coverage modes of operation. Forexample, the narrowband UE may be able to support coverage enhancementsup to 20 dB.

As used herein, devices with limited communication resources, e.g.smaller bandwidth, may be referred to generally as narrowband UEs.Similarly, legacy devices, such as legacy and/or advanced UEs (e.g., inLTE) may be referred to generally as wideband UEs. Generally, widebandUEs are capable of operating on a larger amount of bandwidth thannarrowband UEs.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular RAT andmay operate on one or more frequencies. A RAT may also be referred to asa radio technology, an air interface, etc. A frequency may also bereferred to as a carrier, a frequency channel, etc. Each frequency maysupport a single RAT in a given geographic area in order to avoidinterference between wireless networks of different RATs. In some cases,NR or 5G RAT networks may be deployed.

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communications systems, such as NR. NR may supportvarious wireless communication services, such as millimeter wave (mmW)targeting high carrier frequency (e.g., 60 GHz), massive multiple inputmultiple output (MIMO), sub-6 GHz systems, etc. NR may utilize OFDM witha CP on the uplink and downlink and include support for half-duplexoperation using TDD. A single component carrier bandwidth of 100 MHZ maybe supported. NR resource blocks may span 12 sub-carriers with asubcarrier bandwidth of 75 kHz over a 0.1 ms duration. Each radio framemay consist of 2 half frames, each half frame consisting of 5 subframeswith a length of 10 ms. Consequently, each subframe may have a length of1 ms. Each subframe may indicate a link direction (i.e., DL or UL) fordata transmission and the link direction for each subframe may bedynamically switched. Each subframe may include DL/UL data as well asDL/UL control data. UL and DL subframes for NR (in one referenceexample) are described in more detail below with respect to FIGS. 8 and9. Beamforming may be supported and beam direction may be dynamicallyconfigured. MIMO transmissions with precoding may also be supported.MIMO configurations in the DL may support up to 8 transmit antennas withmulti-layer DL transmissions up to 8 streams and up to 2 streams per UE.Multi-layer transmissions with up to 2 streams per UE may be supported.Aggregation of multiple cells may be supported with up to 8 servingcells. Alternatively, NR may support a different air interface, otherthan an OFDM-based. NR networks may include entities such central unitsor distributed units.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. Within the present disclosure, as discussed further below,the scheduling entity may be responsible for scheduling, assigning,reconfiguring, and releasing resources for one or more subordinateentities. That is, for scheduled communication, subordinate entitiesutilize resources allocated by the scheduling entity.

Base stations are not the only entities that may function as ascheduling entity. That is, in some examples, a UE may function as ascheduling entity, scheduling resources for one or more subordinateentities (e.g., one or more other UEs). In this example, the UE isfunctioning as a scheduling entity, and other UEs utilize resourcesscheduled by the UE for wireless communication. A UE may function as ascheduling entity in a peer-to-peer (P2P) network, and/or in a meshnetwork. In a mesh network example, UEs may optionally communicatedirectly with one another in addition to communicating with thescheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

FIG. 2 shows a block diagram of a design of BS 110 and UE 120, which maybe one of the base stations and one of the UEs in FIG. 1. BS 110 may beequipped with T antennas 234 a through 234 t, and UE 120 may be equippedwith R antennas 252 a through 252 r, where in general T≥1 and R≥1. Oneor more components of the BS 110 and UE 120 may be used to practiceaspects of the present disclosure.

At BS 110, a transmit processor 220 may receive data from a data source212 for one or more UEs, select one or more modulation and codingschemes (MCS) for each UE based on CQIs received from the UE, process(e.g., encode and modulate) the data for each UE based on the MCS(s)selected for the UE, and provide data symbols for all UEs. Transmitprocessor 220 may also process system information (e.g., for SRPI, etc.)and control information (e.g., CQI requests, grants, upper layersignaling, etc.) and provide overhead symbols and control symbols.Processor 220 may also generate reference symbols for reference signals(e.g., the CRS) and synchronization signals (e.g., the PSS and SSS). Atransmit (TX) multiple-input multiple-output (MIMO) processor 230 mayperform spatial processing (e.g., precoding) on the data symbols, thecontrol symbols, the overhead symbols, and/or the reference symbols, ifapplicable, and may provide T output symbol streams to T modulators(MODs) 232 a through 232 t. Each modulator 232 may process a respectiveoutput symbol stream (e.g., for OFDM, etc.) to obtain an output samplestream. Each modulator 232 may further process (e.g., convert to analog,amplify, filter, and upconvert) the output sample stream to obtain adownlink signal. T downlink signals from modulators 232 a through 232 tmay be transmitted via T antennas 234 a through 234 t, respectively.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom base station 110 and/or other base stations and may providereceived signals to demodulators (DEMODs) 254 a through 254 r,respectively. Each demodulator 254 may condition (e.g., filter, amplify,downconvert, and digitize) its received signal to obtain input samples.Each demodulator 254 may further process the input samples (e.g., forOFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtainreceived symbols from all R demodulators 254 a through 254 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 258 may process (e.g., demodulateand decode) the detected symbols, provide decoded data for UE 120 to adata sink 260, and provide decoded control information and systeminformation to a controller/processor 280. A channel processor maydetermine RSRP, RSSI, RSRQ, CQI, etc.

On the uplink, at UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports comprising RSRP, RSSI, RSRQ, CQI, etc.) fromcontroller/processor 280. Processor 264 may also generate referencesymbols for one or more reference signals. The symbols from transmitprocessor 264 may be precoded by a TX MIMO processor 266 if applicable,further processed by modulators 254 a through 254 r (e.g., for SC-FDM,OFDM, etc.), and transmitted to base station 110. At base station 110,the uplink signals from UE 120 and other UEs may be received by antennas234, processed by demodulators 232, detected by a MIMO detector 236 ifapplicable, and further processed by a receive processor 238 to obtaindecoded data and control information sent by UE 120. Processor 238 mayprovide the decoded data to a data sink 239 and the decoded controlinformation to controller/processor 240. Base station 110 may includecommunication unit 244 and communicate to network controller 130 viacommunication unit 244. Network controller 130 may include communicationunit 294, controller/processor 290, and memory 292.

Controllers/processors 240 and 280 and/or any other component(s) in FIG.2 may direct the operation at BS 110 and UE 120, respectively, toperform techniques presented herein for enabling HARQ-ACK bundling inHD-FDD (e.g., for eMTC UEs). For example, controller/processor 280and/or other controllers/processors and modules at UE 120 may perform ordirect operations by the UE in FIG. 11, and/or other processes for thetechniques described herein. By enabling controller/processor 280 and/orother modules at the UE 120 to perform operations in FIG. 11 (e.g., forproviding HARQ-ACK feedback for a bundled transmission), thecontroller/processor 280 can significantly increase the peak data ratefor UE 120 (relative to conventional HARQ ACK feedback techniques). Thecontroller/processor 240 and/or other controllers/processors and modulesat BS 110 may perform operations by the BS in FIG. 10 and/or otherprocesses for the techniques described herein. By enablingcontroller/processor 240 and/or other modules at BS 110 to performoperations in FIG. 10 (e.g., for determining ACK parameters for a UE touse for providing HARQ-ACK feedback for a bundled transmission), thecontroller/processor 240 can significantly increase the peak data ratefor UE 120 (relative to conventional HARQ ACK feedback techniques).Memories 242 and 282 may store data and program codes for base station110 and UE 120, respectively. A scheduler 246 may schedule UEs for datatransmission on the downlink and/or uplink.

FIG. 3 shows an exemplary frame structure 300 for FDD in atelecommunications system (e.g., LTE). The transmission timeline foreach of the downlink and uplink may be partitioned into units of radioframes. Each radio frame may have a predetermined duration (e.g., 10milliseconds (ms)) and may be partitioned into 10 subframes with indicesof 0 through 9. Each subframe may include two slots. Each radio framemay thus include 20 slots with indices of 0 through 19. Each slot mayinclude L symbol periods, e.g., seven symbol periods for a normal cyclicprefix (as shown in FIG. 3) or six symbol periods for an extended cyclicprefix. The 2L symbol periods in each subframe may be assigned indicesof 0 through 2L−1.

In certain telecommunications (e.g., LTE), a BS may transmit a primarysynchronization signal (PSS) and a secondary synchronization signal(SSS) on the downlink in the center of the system bandwidth for eachcell supported by the BS. The PSS and SSS may be transmitted in symbolperiods 6 and 5, respectively, in subframes 0 and 5 of each radio framewith the normal cyclic prefix, as shown in FIG. 3. The PSS and SSS maybe used by UEs for cell search and acquisition. The BS may transmit acell-specific reference signal (CRS) across the system bandwidth foreach cell supported by the BS. The CRS may be transmitted in certainsymbol periods of each subframe and may be used by the UEs to performchannel estimation, channel quality measurement, and/or other functions.The BS may also transmit a physical broadcast channel (PBCH) in symbolperiods 0 to 3 in slot 1 of certain radio frames. The PBCH may carrysome system information. The BS may transmit other system informationsuch as system information blocks (SIBs) on a physical downlink sharedchannel (PDSCH) in certain subframes. The BS may transmit controlinformation/data on a physical downlink control channel (PDCCH) in thefirst B symbol periods of a subframe, where B may be configurable foreach subframe. The BS may transmit traffic data and/or other data on thePDSCH in the remaining symbol periods of each subframe.

In other systems (e.g., such NR or 5G systems), a Node B may transmitthese or other signals in these locations or in different locations ofthe subframe.

FIG. 4 shows two exemplary subframe formats 410 and 420 with the normalcyclic prefix. The available time frequency resources may be partitionedinto resource blocks. Each resource block may cover 12 subcarriers inone slot and may include a number of resource elements. Each resourceelement may cover one subcarrier in one symbol period and may be used tosend one modulation symbol, which may be a real or complex value.

Subframe format 410 may be used for two antennas. A CRS may betransmitted from antennas 0 and 1 in symbol periods 0, 4, 7 and 11. Areference signal is a signal that is known a priori by a transmitter anda receiver and may also be referred to as pilot. A CRS is a referencesignal that is specific for a cell, e.g., generated based on a cellidentity (ID). In FIG. 4, for a given resource element with label Ra, amodulation symbol may be transmitted on that resource element fromantenna a, and no modulation symbols may be transmitted on that resourceelement from other antennas. Subframe format 420 may be used with fourantennas. A CRS may be transmitted from antennas 0 and 1 in symbolperiods 0, 4, 7 and 11 and from antennas 2 and 3 in symbol periods 1 and8. For both subframe formats 410 and 420, a CRS may be transmitted onevenly spaced subcarriers, which may be determined based on cell ID.CRSs may be transmitted on the same or different subcarriers, dependingon their cell IDs. For both subframe formats 410 and 420, resourceelements not used for the CRS may be used to transmit data (e.g.,traffic data, control data, and/or other data).

The PSS, SSS, CRS and PBCH in LTE are described in 3GPP TS 36.211,entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); PhysicalChannels and Modulation,” which is publicly available.

An interlace structure may be used for each of the downlink and uplinkfor FDD in certain telecommunications systems (e.g., LTE). For example,Q interlaces with indices of 0 through Q−1 may be defined, where Q maybe equal to 4, 6, 8, 10, or some other value. Each interlace may includesubframes that are spaced apart by Q frames. In particular, interlace qmay include subframes q, q+Q, q+2Q, etc., where q E {0, . . . , Q−1}.

The wireless network may support hybrid automatic retransmission request(HARQ) for data transmission on the downlink and uplink. For HARQ, atransmitter (e.g., a BS) may send one or more transmissions of a packetuntil the packet is decoded correctly by a receiver (e.g., a UE) or someother termination condition is encountered. For synchronous HARQ, alltransmissions of the packet may be sent in subframes of a singleinterlace. For asynchronous HARQ, each transmission of the packet may besent in any subframe.

A UE may be located within the coverage of multiple BSs. One of theseBSs may be selected to serve the UE. The serving BS may be selectedbased on various criteria such as received signal strength, receivedsignal quality, pathloss, etc. Received signal quality may be quantifiedby a signal-to-noise-and-interference ratio (SINR), or a referencesignal received quality (RSRQ), or some other metric. The UE may operatein a dominant interference scenario in which the UE may observe highinterference from one or more interfering BSs.

Example Narrowband Communications

The focus of traditional LTE design (e.g., for legacy “non MTC” devices)is on the improvement of spectral efficiency, ubiquitous coverage, andenhanced quality of service (QoS) support. Current LTE system downlink(DL) and uplink (UL) link budgets are designed for coverage of high enddevices, such as state-of-the-art smartphones and tablets, which maysupport a relatively large DL and UL link budget.

However, as described above, one or more UEs in the wirelesscommunication network (e.g., wireless communication network 100) may bedevices that have limited communication resources, such as narrowbandUEs, as compared to other (wideband) devices in the wirelesscommunication network. For narrowband UEs, various requirements may berelaxed as only a limited amount of information may need to beexchanged. For example, maximum bandwidth may be reduced (e.g., relativeto wideband UEs), a single receive radio frequency (RF) chain may beused, peak rate may be reduced (e.g., a maximum of 1000 bits for atransport block size), transmit power may be reduced, Rank 1transmission may be used, and half duplex operation may be performed.

FIGS. 5A and 5B illustrate examples of how UEs in MTC and/or eMTCoperation may co-exist within a wideband system (e.g., 1.4/3/5/10/15/20MHz), such as LTE. As illustrated in the example frame structure of FIG.5A, subframes 510 associated with MTC and/or eMTC operation may be timedivision multiplexed (TDM) with regular subframes 520 associated withLTE (or some other RAT).

As mentioned above, MTC and/or eMTC operation may be supported in thewireless communication network (e.g., in coexistence with LTE or someother RAT). That is, eMTC may co-exist with other LTE services withinthe same bandwidth, support FDD, TDD and half duplex (HD) modes, re-useexisting LTE base stations with software update (e.g., according toE-UTRAN vendors), etc. FIGS. 5A and 5B, for example, illustrate anexample of how UEs in MTC and/or eMTC operation may co-exist within awideband system (e.g., 1.4/3/5/10/15/20 MHz), such as LTE.

As illustrated in the example frame structure of FIG. 5A, subframes 510associated with MTC and/or eMTC operation may be time divisionmultiplexed (TDM) with regular subframes 520 associated with LTE (orsome other RAT). Additionally or alternatively, as illustrated in theexample frame structure of FIG. 5B, one or more narrowband regions 560,562 used by narrowband UEs may be frequency division multiplexed withinthe wider bandwidth 550 supported by LTE. Multiple narrowband regions,with each narrowband region spanning a bandwidth that is no greater thana total of 6 RBs, may be supported for MTC and/or eMTC operation. Insome cases, such as LTE Release 13, each eMTC UE may operate (e.g.,monitor/receive/transmit) within one narrowband region (e.g., at 1.4 MHzor 6 RBs) at a time. In other cases, such as LTE Release 14, eMTC UEsmay operate on a 5 MHz narrowband region (e.g., using 25 RBs).

At any given time, eMTC UEs may re-tune to other narrowband regions inthe wider system bandwidth. That is, an eMTC UE may switch or hopbetween multiple narrowband regions in order to reduce interference. Insome examples, multiple eMTC UEs may be served by the same narrowbandregion. In yet other examples, different combinations of eMTC UEs may beserved by one or more same narrowband regions and/or one or moredifferent narrowband regions.

As shown, the eMTC UEs may operate (e.g., monitor/receive/transmit)within the narrowband regions for various different operations. Forexample, as shown in FIG. 5B, a first narrowband region 560 of asubframe 552 may be monitored by one or more eMTC UEs for either a PSS,SSS, PBCH, MTC signaling, or paging transmission from a BS in thewireless communication network. As also shown in FIG. 5B, a secondnarrowband region 562 of a subframe 554 may be used by eMTC UEs totransmit a RACH or data previously configured in signaling received froma BS. In some cases, the second narrowband region may be utilized by thesame UEs that utilized the first narrowband region (e.g., the UEs mayhave re-tuned to the second narrowband region to transmit aftermonitoring in the first narrowband region). In some cases (although notshown), the second narrowband region may be utilized by different UEsthan the UEs that utilized the first narrowband region.

Certain systems may provide eMTC UEs with coverage enhancements of up to20 dB to support low cost MTC devices (e.g., such as BL/CE users) with asingle antenna and a basic receiver, and/or located in cell edges toconnect. That is, eMTC UEs and eNB may perform measurements at low SNRs(e.g., −15 dB to −20 dB). In order to achieve coverage enhancement,multiple repetitions/instances (e.g., bundling) of the same message(with different redundancy versions) may be transmitted over one or moresubframes.

Although the examples described herein assume a narrowband of 6 RBs,those skilled in the art will recognize that the techniques presentedherein may also be applied to different sizes of narrowband regions(e.g., 25 RBs).

In the case of NB-IoT, the wireless communication network (e.g., LTERelease 13, or greater) may support deployments using one physicalresource block (PRB) (e.g., 180 kHz+20 kHz guard band). NB-IoTdeployments may utilize higher layer components of LTE and hardware toallow for reduced fragmentation and cross compatibility with, forexample, NB-LTE and eMTC. In one case, NB-IoT may be deployed in-bandand coexist with legacy GSM/WCDMA/LTE system(s) deployed in the samefrequency band. Wideband LTE channel, for example, may be deployed invarious bandwidths between 1.4 MHz to 20 MHz, and there may be adedicated PRB for use by NB-IoT, or the RBs allocated for NB-IoT may bedynamically allocated (e.g., by an eNB). In an in-band deployment, onePRB, or 180 kHz, of a wideband LTE channel may be used for NB-IoT. Insome deployments, NB-IoT may be deployed standalone. In a standalonedeployment, one 180 kHz carrier may be used to carry NB-IoT traffic andGSM spectrum may be reused. In some deployments, NB-IoT may be deployedin the unused resource blocks within a LTE carrier guard-band.

NB-IoT may support single-tone and multi-tone assignments. For example,in uplink, 15 kHz or 3.75 kHz tone spacing may be used with single toneallocation or multiple tone allocation. For 15 kHz tone or subcarrierspacing, up to 12 tones or subcarriers can be used in a resource unitwith single tone allocation and for 3.75 kHz tone spacing up to 48 tonescan be used in a resource unit with single tone allocation.

Example NR/5G RAN Architecture

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communications systems, such as NR or 5Gtechnologies.

New radio (NR) may refer to radios configured to operate according to anew air interface (e.g., other than Orthogonal Frequency DivisionalMultiple Access (OFDMA)-based air interfaces) or fixed transport layer(e.g., other than Internet Protocol (IP)). NR may utilize OFDM with a CPon the uplink and downlink and include support for half-duplex operationusing TDD. NR may include Enhanced Mobile Broadband (eMBB) servicetargeting wide bandwidth (e.g. 80 MHz beyond), millimeter wave (mmW)targeting high carrier frequency (e.g. 60 GHz), massive MTC (mMTC)targeting non-backward compatible MTC techniques, mission criticaltargeting ultra reliable low latency communications (URLLC) service,etc.

In NR, the RAN may include a central unit (CU) and distributed units(DUs). A NR BS (e.g., gNB, 5G Node B, Node B, transmit receive point(TRP), access point (AP)) may correspond to one or multiple BSs. NRcells can be configured as access cells (ACells) or data only cells(DCells). For example, the RAN (e.g., a central unit or distributedunit) can configure the cells. DCells may be cells used for carrieraggregation or dual connectivity, but not used for initial access, cellselection/reselection, or handover. In some cases, DCells may nottransmit synchronization signals—in some case cases, DCells may transmitSS. NR BSs may transmit downlink signals to UEs indicating the celltype. Based on the cell type indication, the UE may communicate with theNR BS. For example, the UE may determine NR BSs to consider for cellselection, access, handover, and/or measurement based on the indicatedcell type.

FIG. 6 illustrates an example logical architecture of a distributed RAN600, according to aspects of the present disclosure. A 5G access node606 may include an access node controller (ANC) 602. The ANC may be acentral unit (CU) of the distributed RAN 600. The backhaul interface tothe next generation core network (NG-CN) 604 may terminate at the ANC.The backhaul interface to neighboring next generation access nodes(NG-ANs) may terminate at the ANC. The ANC may include one or more TRPs608 (which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs,gNB, or some other term). As described above, a TRP may be usedinterchangeably with “cell.”

The TRPs 608 may be a distributed unit (DU). The TRPs may be connectedto one ANC (ANC 602) or more than one ANC (not illustrated). Forexample, for RAN sharing, radio as a service (RaaS), and servicespecific AND deployments, the TRP may be connected to more than one ANC.A TRP may include one or more antenna ports. The TRPs may be configuredto individually (e.g., dynamic selection) or jointly (e.g., jointtransmission) serve traffic to a UE.

The local architecture 600 may be used to illustrate fronthauldefinition. The architecture may be defined that support fronthaulingsolutions across different deployment types. For example, thearchitecture may be based on transmit network capabilities (e.g.,bandwidth, latency, and/or jitter).

The architecture may share features and/or components with LTE.According to aspects, the next generation AN (NG-AN) 610 may supportdual connectivity with NR. The NG-AN may share a common fronthaul forLTE and NR.

The architecture may enable cooperation between and among TRPs 608. Forexample, cooperation may be preset within a TRP and/or across TRPs viathe ANC 602. According to aspects, no inter-TRP interface may beneeded/present.

According to aspects, a dynamic configuration of split logical functionsmay be present within the architecture 600. The PDCP, RLC, MAC protocolmay be adaptably placed at the ANC or TRP.

According to certain aspects, a BS may include a central unit (CU)(e.g., ANC 602) and/or one or more distributed units (e.g., one or moreTRPs 608).

FIG. 7 illustrates an example physical architecture of a distributed RAN700, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 702 may host core network functions. The C-CU may becentrally deployed. C-CU functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 704 may host one or more ANC functions.Optionally, the C-RU may host core network functions locally. The C-RUmay have distributed deployment. The C-RU may be closer to the networkedge.

A distributed unit (DU) 706 may host one or more TRPs. The DU may belocated at edges of the network with radio frequency (RF) functionality.

FIG. 8 is a diagram 800 showing an example of a DL-centric subframe. TheDL-centric subframe may include a control portion 802. The controlportion 802 may exist in the initial or beginning portion of theDL-centric subframe. The control portion 802 may include variousscheduling information and/or control information corresponding tovarious portions of the DL-centric subframe. In some configurations, thecontrol portion 802 may be a physical DL control channel (PDCCH), asindicated in FIG. 8. The DL-centric subframe may also include a DL dataportion 804. The DL data portion 804 may sometimes be referred to as thepayload of the DL-centric subframe. The DL data portion 804 may includethe communication resources utilized to communicate DL data from thescheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE).In some configurations, the DL data portion 804 may be a physical DLshared channel (PDSCH).

The DL-centric subframe may also include a common UL portion 806. Thecommon UL portion 806 may sometimes be referred to as an UL burst, acommon UL burst, and/or various other suitable terms. The common ULportion 806 may include feedback information corresponding to variousother portions of the DL-centric subframe. For example, the common ULportion 806 may include feedback information corresponding to thecontrol portion 802. Non-limiting examples of feedback information mayinclude an ACK signal, a NACK signal, a HARQ indicator, and/or variousother suitable types of information. The common UL portion 806 mayinclude additional or alternative information, such as informationpertaining to random access channel (RACH) procedures, schedulingrequests (SRs), and various other suitable types of information. Asillustrated in FIG. 8, the end of the DL data portion 804 may beseparated in time from the beginning of the common UL portion 806. Thistime separation may sometimes be referred to as a gap, a guard period, aguard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the subordinate entity (e.g., UE)) to UL communication(e.g., transmission by the subordinate entity (e.g., UE)). One ofordinary skill in the art will understand that the foregoing is merelyone example of a DL-centric subframe and alternative structures havingsimilar features may exist without necessarily deviating from theaspects described herein.

FIG. 9 is a diagram 900 showing an example of an UL-centric subframe.

The UL-centric subframe may include a control portion 902. The controlportion 902 may exist in the initial or beginning portion of theUL-centric subframe. The control portion 902 in FIG. 9 may be similar tothe control portion 802 described above with reference to FIG. 8. TheUL-centric subframe may also include an UL data portion 904. The UL dataportion 904 may sometimes be referred to as the payload of theUL-centric subframe. The UL portion may refer to the communicationresources utilized to communicate UL data from the subordinate entity(e.g., UE) to the scheduling entity (e.g., UE or BS). In someconfigurations, the control portion 902 may be a physical DL controlchannel (PDCCH).

As illustrated in FIG. 9, the end of the control portion 902 may beseparated in time from the beginning of the UL data portion 904. Thistime separation may sometimes be referred to as a gap, guard period,guard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the scheduling entity) to UL communication (e.g.,transmission by the scheduling entity). The UL-centric subframe may alsoinclude a common UL portion 906. The common UL portion 906 in FIG. 9 maybe similar to the common UL portion 806 described above with referenceto FIG. 8. The common UL portion 906 may additionally or alternativelyinclude information pertaining to channel quality indicator (CQI),sounding reference signals (SRSs), and various other suitable types ofinformation. One of ordinary skill in the art will understand that theforegoing is merely one example of an UL-centric subframe andalternative structures having similar features may exist withoutnecessarily deviating from the aspects described herein.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

In one example, a frame may include both UL centric subframes and DLcentric subframes. In this example, the ratio of UL centric subframes toDL subframes in a frame may be dynamically adjusted based on the amountof UL data and the amount of DL data that are transmitted. For example,if there is more UL data, then the ratio of UL centric subframes to DLsubframes may be increased. Conversely, if there is more DL data, thenthe ratio of UL centric subframes to DL subframes may be decreased.

Example Methods and Apparatus for Enabling Support of HARQ-ACK Bundlingin Hd-FDD for eMTC

Some of the focus of further enhancements for eMTC has been on thesupport of positioning, multicast, mobility enhancements and higher datarates. In some cases, however, it can be difficult to achieve higherdata rates for certain UEs (e.g., HD-FDD UEs), due in part, to currentHARQ feedback techniques. For example, in eMTC, the peak data rate of aHD-FDD UE may be affected by the timeline relationships and HD guardsubframe. With current HARQ feedback techniques, however, the UEtypically sends HARQ feedback (for multiple transmissions) acrossmultiple subframes. Thus, it may be difficult to maximize the peak datarate for such UEs, since the number of available downlink subframes maybe limited. As a reference example, the maximum data rate for a HD-FDDUE may be 300 kbps, as a single radio frame may include three PDSCHsubframes, three PUCCH subframes, two HD guard subframes and twonon-PDSCH subframes due to cross-subframes scheduling.

To support higher data rates, aspects presented herein providetechniques and apparatus for enabling HARQ-ACK bundling in HD-FDD forcommunication systems such as eMTC. HARQ-ACK bundling may be supportedin at least one of CE Mode A in HD-FDD, CE Mode B, CE Mode A in FD-FDD,physical uplink control channel (PUCCH) repetition case, PDSCHrepetition case, machine type communication physical downlink controlchannel (MPDCCH) repetition case, etc.

In general, one or more HARQ-ACK bundles may be supported for PDSCHscheduling before switching to UL. The HARQ-ACK bundle size may bedefined as the number of PDSCH transmissions (corresponding to differentHARQ processes) with a joint HARQ-ACK feedback. In some cases, themaximum HARQ-ACK bundle size may be four. There may be one or moreHARQ-ACK bundles before a UE switches to UL.

By using the HARQ-ACK bundling techniques described herein, the systemcan increase DL throughput for half duplex operation. For example, inthe above described case where the maximum data rate was limited to 300kbps, the data rate may be increased to 500 kbps (from 300 kpbs) if theHARQ-ACK for the PDSCH can be multiplexed in a single subframe (e.g.,instead of three subframes). Note, however, that this is just oneexample of how the techniques described herein can further increase DLthroughput for UEs, and that, in some cases, aspects presented hereinmay allow for a peak data rate greater than 500 kbps.

FIG. 10 is a flow diagram illustrating example operations 1000 forwireless communications, in accordance with certain aspects of thepresent disclosure. The operations 1000 may be performed, for example,by a base station (e.g., eNB 110).

The operations 1000 begin, at 1002, where the BS determines one or moreACK parameters to be used for acknowledging a bundled transmission thatincludes one or more instances of a channel across one or moresubframes. The channel can be a data channel (e.g., PDSCH), controlchannel (e.g., MPDCCH), etc. The transmission may be from the BS and/orfrom another BS.

At 1004, the BS signals an indication of the one or more ACK parametersto a UE (e.g., a eMTC UE such as UE 120). The one or more ACK parametersmay include a first ACK parameter that conveys a size of the bundledtransmission and a second ACK parameter that conveys an amount of timefor the UE to delay acknowledging a data transmission in an instance ofthe channel after receiving the data transmission.

FIG. 11 is a flow diagram illustrating example operations 1100 forwireless communications, in accordance with certain aspects of thepresent disclosure. The operations 1100 may be performed, for example,by a UE (e.g., eMTC UE, such as UE 120).

The operations 1100 begin, at 1102, where the UE receives an indicationof one or more ACK parameters to use for acknowledging a bundledtransmission that includes one or more instances of a channel across oneor more subframes. The channel can be a data channel (e.g., PDSCH),control channel (e.g., MPDCCH), etc. The one or more ACK parameters mayinclude a first ACK parameter that conveys a size of the bundledtransmission and a second ACK parameter that conveys an amount of timefor the UE to delay acknowledging a data transmission in an instance ofthe channel after receiving the data transmission. At 1104, the UEacknowledges the bundled transmission in accordance with the one or moreACK parameters.

In some aspects, the BS may determine the ACK parameters based in parton a type and/or capability of the UE. For example, in some cases, theBS may determine a first set ACK parameters (to enable HARQ ACKbundling) for BL/CE devices, and may determine a second set of ACKparameters for non-HARQ ACK bundling for non-BL/CE devices. In somecases, the BS may determine to enable HARQ ACK bundling for BL/CEdevices operating in HD-FDD and that support at least one of HARQ ACKbundling or dynamic ACK timing. In some aspects, the ACK parameters maybe determined based on the CE mode(s) supported by the UE. For example,the BS may determine ACK parameters to enable HARQ ACK bundling for UEsthat support CE mode A, and determine ACK parameters for non-HARQ ACKbundling for UEs that support CE mode B. In some aspects, the BS mayselect/determine the ACK parameters from a predetermined number ofcandidate values. For example, as described below, in some cases, thefirst ACK parameter may signal a size between 1 and 4, and the secondACK parameter may signal a delay value in one or more different rangesof values.

The UE may signal one or more parameters indicating the UE's capabilityto support at least one of BL/CE operation, HD-FDD operation, CEmode(s), CE levels, HARQ-ACK bundling, dynamic ACK timing, etc. If theUE is capable of supporting bundling and/or dynamic ACK timing (e.g., todelay transmission of an ACK), the BS may configure the UE to supportbundling and/or dynamic ACK timing via radio resource control (RRC)signaling.

In one aspect, the BS and/or UE may determine the ACK parameters foreach instance of a control channel (e.g., MPDCCH) associated with eachinstance of the data channel (e.g., PDSCH) in the bundled transmission,such that an ACK (for a group of instances) is sent in the associateduplink subframe by the UE. In one aspect, the ACK parameters may includeat least one delay value parameter (e.g., second ACK parameter) thatconveys an amount of time for the UE to delay acknowledging a datatransmission in an instance of the data channel after receiving the datatransmission.

Assuming, for example, that the bundled transmission includes aninstance of a data channel (e.g., PDSCH) transmitted on each of threesubframes (subframes 1, 2, and 3), the BS can signal in the controlchannel (e.g., MPDCCH) associated with each data channel instance thedelay (e.g., number of subframes) the UE should wait before sending anACK. That is, each delay parameter can signal the number of subframesbetween the end of the data channel and the start of ACK/NACK. Forexample, assuming the BS wants the UE to send an ACK on subframe 7 thatacknowledges the bundled data transmission (e.g., from subframes 1-3),the delay parameter for subframe 1 may indicate a delay of 6 subframes,the delay parameter for subframe 2 may indicate a delay of 5 subframes,and the delay parameter for subframe 3 may indicate a delay of 4subframes. In this manner, the BS can determine delay parameters foreach instance in the bundled transmission, such that the UE sends an ACKin a single uplink subframe. When the BS signals the delay, the UE mayimplicitly determine the bundle group by identifying the potentialuplink subframe and determine how many MPDCCH/PDSCH were received thatrequested ACK/NACK to be sent on that subframe.

In some aspects, an ACK delay indicator field (that indicates the delay“D”) can be added to the downlink control information (DCI) (e.g., inMPDCCH) to enable ACK bundling. In some cases, the ACK delay indicatorfield can indicate a full set of delay values. For example, the ACKdelay indicator field may use three bits to indicate at least one ofdelays in the set D={4,5,6,7,8,9,10,11}. Upon receiving the delayindicator, the UE may transmit an ACK corresponding to the PDSCH endingon subframe X at subframe X+D. However, in some cases, the UE maytransmit ACK on subframe X+D only if, in subframe X+D, the UE detectedall N MPDCCHs in the bundle and decoded the corresponding PDSCHs. Thatis, the UE may transmit NACK if it fails to detect at least onecorresponding MPDCCH and/or PDSCH.

In some cases, the ACK delay indicator field (e.g., three bit field orother amount of bits) can indicate a subsampled set of delay values. Insome cases, the ACK delay indicator field can indicate a subsampled setof delay values that specifies the minimum delay the UE should use afterreceiving a data transmission. For example, the ACK delay indicatorfield may use two bits to indicate at least one of the minimum delays inthe set D={4, 6, 8, 10}. In these cases, upon receiving the delayindicator, the UE may try a hypothesis of X+D, X+D+1 for the ACKsubframe for PDSCH ending at subframe X. The UE may determine, based onthe number of MPDCCH it has detected in each subframe, which of thesubframes is the correct subframe to send the ACK. For example, the UEmay count the number of MPDCCH/PDSCH it detects corresponding tosubframes X+D, X+D+1, and choose the smaller of the two subframes thatmatches the number of PDSCH in the bundle criteria.

While using a two bit ACK delay indicator field may save a bit (e.g.,compared to using a three bit ACK delay indicator field), in some cases,the two bit ACK delay indicator field may affect the schedulingdecisions at the eNB. For example, if the UE determines that the numberof detected MPDCCHs do not match (e.g., is not N), the UE may transmitNACK on these subframes if the UE is able to reliably determine thesubframe. The UE may puncture the ACK/NACK otherwise.

In some aspects, the one or more ACK parameters may include a parameter(e.g., first ACK parameter) that conveys the size of the bundledtransmission. For example, the size of the bundled transmission maycorrespond to the number of the instances of the channel associated withthe bundled transmission. In one aspect, (e.g., when bundling isconfigured by RRC), a field that indicates the number of PDSCH in thebundle can be added to DCI (in the downlink grant) to enable ACKbundling. For example, in one case, the field can indicate the number Nof PDSCH in the bundle, where N is selected from {1,2,3,4}.

In one aspect, the ACK parameters may include a parameter that conveysthe size of the bundled transmission and a parameter that indicateswhether the channel has been transmitted in a last instance of the oneor more instances in the bundled transmission (e.g., “last instance inbundle” indication). For example, in one implementation, the BS mayjointly code the number N of PDSCH in the bundle with a “last instancein bundle” bit. In some cases, the UE may just have to know the size ofthe bundle in situations where the UE receives the last instance in thebundle, as such information may be sufficient for the UE to determine ifit received all PDSCH in the bundle. Therefore, in some cases, the BSmay set the parameter that conveys the size of the bundled transmissionto zero or other dummy values such as max allowed bundle size if thechannel has not been transmitted in the last instance of the instancesin the bundled transmission (i.e., the “last instance in bundle” bit is0). On the other hand, the BS may set the parameter that conveys thesize of the bundled transmission to the correct size of the bundledtransmission if the channel has been transmitted in the last instance ofthe instances in the bundled transmission.

As one reference example of jointly coding the number N of PDSCH in thebundle with the “last instance in bundle” bit, if bundle sizes of 1, 2,4 are supported, the BS may signal one of the following four states tothe UE: (1) ‘00’: not last instance; (2) ‘01’: last instance, 1 instancein bundle; (3) ‘10’: last instance, 2 instances in bundle; (4) ‘11’:last instance, 4 instances in bundle. Those of ordinary skill in theart, however, will recognize that other values may be used for differentbundle sizes. In some cases, the BS may use three bits to support allbundle sizes from 1 to 4. In general, the BS may use any number of bitsto support different bundle sizes.

In some aspects, the ACK parameters may include a parameter that conveysthe size of the bundled transmission and a parameter that conveys avalue of a downlink assignment index (DAI) for the bundled transmission.For example, the BS can signal the DAI counter in addition to the “lasinstance in bundle” bit by jointly coding the two.

Such information may give the UE more visibility regarding which PDSCHwas potentially lost.

In some aspects, as opposed to transmitting a “last instance in bundlebit,” the size of the bundled transmission (indicated for a giveninstance of the channel) may implicitly indicate whether the channel hasbeen transmitted in a last instance of the one or more instances in thebundled transmission. For example, for each instance of the channelprior to a last instance of the channel, the BS may set the size of thebundled transmission (for that instance) to a value that is greater thana number of that instance in the one or more instances of the channel.Assume, for example, that the bundled transmission includes fourinstances of a data channel across four subframes. In this example, theBS may set the size of the bundled transmission for the first instanceto a value greater than “1”, set the size of the bundled transmissionfor the second instance to a value greater than “2”, and set the size ofthe bundled transmission for the third instance to a value greater than“3”. In some aspects, the BS may set the size of the bundledtransmission for each instance (prior to the last instance) to a maximumnumber of allowed instances of the one or more instances of the channelwith uplink ACK on the same uplink subframe. Continuing with the aboveexample, the BS in this case may set the size of the bundledtransmission for each of the first three subframes to “4”.

In this manner, the BS can implicitly indicate to the UE whether thechannel has been transmitted in the last instance of the bundledtransmission. For example, if the UE determines that the indicatedbundle size for a given instance does not match (e.g., is greater than)the number of decoded MPDCCH/PDSCH until that instance, the UE maydetermine that the channel has not been transmitted in the last instanceof the bundled transmission.

In some aspects, the BS may set the size of the bundled transmission toa correct size of the bundled transmission if the channel has beentransmitted in a last instance of the one or more instances in thebundled transmission. Continuing with the above example, for the last(fourth) instance, the BS may set the size of the bundled transmissionto “4” to implicitly indicate that the channel has been transmitted inthe last instance.

In general, the ACK parameters may include any one of or combination ofthe above parameters to enable ACK bundling. For example, in one aspect,the ACK parameters may include the delay parameter D, the number N ofPDSCH in the bundle, and/or the “last instance in the bundle” bit. TheBS may maintain a table that includes the delay, number of instances inthe bundle, and whether the instance is the last instance (e.g., whetherthe channel has been transmitted in a last instance of the instances ofthe channel in the bundled transmission). The BS may set the number ofinstances in the bundle to zero or other values if the instance is notthe last instance. For some delays, the UE may assume that an instanceis not the last instance. For example, if in subframe X the UE receivesan indication that the delay is greater than 7 subframes, the UE mayassume that subframe X is not the last instance in the bundle.

In some aspects, the BS may receive a message from the UE after the BStransmits the instances of the channel across the one or more subframes.The BS may determine, based at least in part on a size of the message,whether the bundled transmission was correctly decoded by the UE. Forexample, in some cases, the message may convey more than one bit ofinformation in the UL subframe. If the message includes a plurality ofbits, the BS may determine, from a first one or more bits of themessage, a number of the instances of the channel that were received bythe UE. In addition, the BS may determine, from a second one or morebits of the message, for a group of instances of the channel, whetherthe channel in each received instance in the group is acknowledged ornegatively acknowledged.

For example, assume that format 2B/channel selection or other methods toconvey more than 1 bit of information in the ACK/NACK resource is used.If the message (from the UE) includes four bits, two bits (of the fourbits) may be used to indicate the number of instances of the channelreceived by the UE and the remaining two bits may be used to indicateACK/NACK for the instances (e.g., first bit for ACK/NACK of PDSCH 1,3and second bit for ACK/NACK of PDSCH 2,4). If the message includes threebits, two bits may be used to indicate the number of instances of thechannel received by the UE, and a single bit for ACK/NACK (e.g., for upto four instances of PDSCH bundled together). If the message includestwo bits, the first bit may be used for ACK/NACK of PDSCH 1,3 and thesecond bit may be used for ACK/NACK of PDSCH 2,4. If the messageincludes a single bit, the single bit may be used to ACK/NACK up to fourPDSCHs bundled together.

In some cases, for the three/four bit options, the BS may not have tosend the number of PDSCHs in the bundle indication (e.g., number ofsubframes/last subframe/DAI, etc.) in the DL DCI. For one bit/two bitcases, the BS may send the number of PDSCHs in the bundle indication inthe DL DCI.

In some aspects, when the UE sends an ACK/NACK that corresponds to agroup of bundled PDSCHs, the UE may send an ACK if all the PDSCHs in thebundle are decoded successfully, and may send a NACK if at least one ofthe MPDCCH corresponding to the bundled PDSCHs is an erasure. In thismanner, the techniques presented herein may provide an ACK bundlingdesign that is robust to MPDCCH erasures (e.g., when the UE fails todetect/decode a MPDCCH).

In some aspects, the UE may determine the size of the bundledtransmission from the ACK parameters communicated in the control region.In some aspects, the UE may determine the size of the bundledtransmission from the number of MPDCCH it has detected that point to thesame UL subframe for ACK. In some aspects, the UE may send an ACK in theUL subframe if (1) the size (e.g., first size) of the bundledtransmission detected from the ACK parameters (in the last receivedinstance of the control channel of the bundled transmission) is equal tothe size (e.g., second size) of the bundled transmission detected fromthe number of MPDCCH that point to the same UL subframe for ACK, and (2)the UE has successfully decoded all the PDSCH associated with that ULsubframe. Otherwise, the UE may send a NACK (e.g., if the first size isnot equal to the second size or if any instance of the PDSCH associatedwith the uplink subframe is decoded incorrectly). For example, the UEmay send an ACK on a subframe if it detects and decodes K MPDCCH/PDSCHscorresponding to that subframe and K is equal to the ACK parameter “sizeof the bundled transmission” in the last decoded DL grant (MPDCCH) inthe bundle.

The ACK bundling design disclosed herein may improve the schedulingflexibility at the eNB. For example, if the eNB is able to communicatethe correct bundling size only in the last instance of the controlchannel, the eNB can change its decision on the bundling size at anytime. For example if the eNB had intended to send a bundle size of 4 and4 contiguous subframes to a UE, it can set bundle size=4 on all 4 PDCCHsassociated with the planned bundle. However, if after transmitting thefirst PDCCH/PDSCH in the bundle, the eNB decides that it wants to use abundle size of 2 as it needs other subframes for other higher prioritydata for other UEs, the eNB can just change the bundle size on nexttransmission of PDCCH and PDSCH to the UE to two and the system operatesas if the eNB intended the bundle size to be two from the beginning. TheACK bundling design disclosed herein may thus not enforce PDSCHtransmission on every subframe. In addition, the techniques disclosedherein allow for a scalable, flexible ACK bundling design that can workwith repetitions of MPDCCH, PDSCH, PUCCH, etc.

Aspects presented herein also provide techniques for simultaneousreception of multiple UL grants.

Similar to ACK bundling, data rate increases in DL and/or UL may beobtained by allowing grants for multiple PDSCH transmissions to be inthe same MPDCCH search space. For half duplex UEs, any subframe used forsending the UL grants in the MPDDCH may reduce the number of availableUL subframes. Additionally, since DL uses cross-subframe scheduling, anysubframes being used for MPDCCH for sending UL grants may reduceavailable resources for sending PDSCH and for sending grants for PDSCH,which may be a limiting factor in low SNR due to the use of largeraggregation levels. Thus, by allowing multiple UL grants to be receivedsimultaneously, the eNB can use the extra scheduling flexibility toincrease the throughputs in the DL or UL or both.

eMTC operation, in general, may allow multiple UL grants to be receivedin the same MPDCCH search space. However, since the UL timeline istypically fixed to start at N+4 (for FDD) where N is the last MPDCCHsubframe on which the grant was received, this configuration may putconstraints on the PUSCH transmission and scheduling of correspondingMPDCCH. For example, with current techniques, it may not be possible tosend multiple UL grants on the same DL subframe.

Accordingly, aspects presented herein provide techniques for increasingthe flexibility for sending multiple UL grants in one MPDCCH searchspace. For example, in one aspect, multiple UL grants may be sent usingseparate MPDCCH, one for each grant without increasing the number ofblind decoding at the UE. Additionally, in one aspect, new fields, suchas the UL assignment index used in TDD, may be added to the DCI payloadto offset the multiple PUSCH transmissions on different set ofsubframes. Alternatively, in some aspects, a common MPDCCH that providesmultiple UL grants can be used.

Advantageously, the techniques presented herein provide a flexible ACKbundling design that can be used to improve DL throughput for halfduplex operation.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).Moreover, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or.” That is, unless specified otherwise, or clearfrom the context, the phrase “X employs A or B” is intended to mean anyof the natural inclusive permutations. That is, the phrase “X employs Aor B” is satisfied by any of the following instances: X employs A; Xemploys B; or X employs both A and B. In addition, the articles “a” and“an” as used in this application and the appended claims shouldgenerally be construed to mean “one or more” unless specified otherwiseor clear from the context to be directed to a singular form. As usedherein, including in the claims, the term “and/or,” when used in a listof two or more items, means that any one of the listed items can beemployed by itself, or any combination of two or more of the listeditems can be employed. For example, if a composition is described ascontaining components A, B, and/or C, the composition can contain Aalone; B alone; C alone; A and B in combination; A and C in combination;B and C in combination; or A, B, and C in combination.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), detecting, ascertaining,identifying, checking, and the like. Also, “determining” may includereceiving (e.g., receiving information), accessing (e.g., accessing datain a memory) and the like. Also, “determining” may include resolving,selecting, choosing, establishing and the like.

In some cases, rather than actually transmitting a frame, a device mayhave an interface to output a frame for transmission. For example, aprocessor may output a frame, via a bus interface, to an RF front endfor transmission. Similarly, rather than actually receiving a frame, adevice may have an interface to obtain a frame received from anotherdevice. For example, a processor may obtain (or receive) a frame, via abus interface, from an RF front end for transmission.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering.

For example, means for determining, means for performing, means fortransmitting, means for receiving, means for sending, means forindicating, means for setting, means for signaling, means foracknowledging, means for configuring, means for bundling, means fordecoding, means for selecting, means for conveying, means foridentifying, and/or means for decoding may include a processing system,which may include one or more processors or other elements, such as thetransmit processor 264, the controller/processor 280, the receiveprocessor 258, and/or antenna(s) 252 of the user equipment 120illustrated in FIG. 2, and/or the transmit processor 220, thecontroller/processor 240, the receive processor 238, and/or antenna(s)234 of the base station 110 illustrated in FIG. 2.

Means for transmitting, means for sending, means for signaling, meansfor indicating, means for acknowledging, and/or means for conveying mayinclude a transmitter, which may include a transmit processor 264,MOD(s) 254, and/or antenna(s) 252 of the user equipment 120 illustratedin FIG. 2, and/or the transmit processor 220, MOD(s) 232, and/orantenna(s) 234 of the base station 110 illustrated in FIG. 2. Means forreceiving may include a receiver, which may include receiver processor258, DEMOD(s) 254, and/or antenna(s) 252 of the user equipment 120illustrated in FIG. 2, and/or the receive processor 238, MOD(s) 232,and/or antenna(s) 234 of the base station 110.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in hardware, an example hardware configuration maycomprise a processing system in a wireless node. The processing systemmay be implemented with a bus architecture. The bus may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system and the overall design constraints.The bus may link together various circuits including a processor,machine-readable media, and a bus interface. The bus interface may beused to connect a network adapter, among other things, to the processingsystem via the bus. The network adapter may be used to implement thesignal processing functions of the PHY layer. In the case of a wirelessnode (see FIG. 1), a user interface (e.g., keypad, display, mouse,joystick, etc.) may also be connected to the bus. The bus may also linkvarious other circuits such as timing sources, peripherals, voltageregulators, power management circuits, and the like, which are wellknown in the art, and therefore, will not be described any further. Theprocessor may be implemented with one or more general-purpose and/orspecial-purpose processors. Examples include microprocessors,microcontrollers, DSP processors, and other circuitry that can executesoftware. Those skilled in the art will recognize how best to implementthe described functionality for the processing system depending on theparticular application and the overall design constraints imposed on theoverall system.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer-readable medium.Software shall be construed broadly to mean instructions, data, or anycombination thereof, whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. The processor may beresponsible for managing the bus and general processing, including theexecution of software modules stored on the machine-readable storagemedia. A computer-readable storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor. By way of example, the machine-readable mediamay include a transmission line, a carrier wave modulated by data,and/or a computer readable storage medium with instructions storedthereon separate from the wireless node, all of which may be accessed bythe processor through the bus interface. Alternatively, or in addition,the machine-readable media, or any portion thereof, may be integratedinto the processor, such as the case may be with cache and/or generalregister files. Examples of machine-readable storage media may include,by way of example, RAM (Random Access Memory), flash memory, phasechange memory, ROM (Read Only Memory), PROM (Programmable Read-OnlyMemory), EPROM (Erasable Programmable Read-Only Memory), EEPROM(Electrically Erasable Programmable Read-Only Memory), registers,magnetic disks, optical disks, hard drives, or any other suitablestorage medium, or any combination thereof. The machine-readable mediamay be embodied in a computer-program product.

A software module may comprise a single instruction, or manyinstructions, and may be distributed over several different codesegments, among different programs, and across multiple storage media.The computer-readable media may comprise a number of software modules.The software modules include instructions that, when executed by anapparatus such as a processor, cause the processing system to performvarious functions. The software modules may include a transmissionmodule and a receiving module. Each software module may reside in asingle storage device or be distributed across multiple storage devices.By way of example, a software module may be loaded into RAM from a harddrive when a triggering event occurs. During execution of the softwaremodule, the processor may load some of the instructions into cache toincrease access speed. One or more cache lines may then be loaded into ageneral register file for execution by the processor. When referring tothe functionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

Also, any connection is properly termed a computer-readable medium. Forexample, if the software is transmitted from a website, server, or otherremote source using a coaxial cable, fiber optic cable, twisted pair,digital subscriber line (DSL), or wireless technologies such as infrared(IR), radio, and microwave, then the coaxial cable, fiber optic cable,twisted pair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a wireless node and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a wirelessnode and/or base station can obtain the various methods upon coupling orproviding the storage means to the device. Moreover, any other suitabletechnique for providing the methods and techniques described herein to adevice can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. A method for wireless communication by a basestation (BS), comprising: determining one or more acknowledgment (ACK)parameters to be used for acknowledging a transmission comprising one ormore instances of a channel across one or more subframes; and signalingan indication of the one or more ACK parameters to a user equipment(UE), wherein the one or more ACK parameters comprise a first ACKparameter that conveys a size of the transmission and a second ACKparameter that conveys an amount of time for the UE to delayacknowledging a data transmission in an instance of the channel afterreceiving the data transmission.
 2. The method of claim 1, wherein: theamount of time comprises one or more subframes; and the size of thetransmission comprises a number of the one or more instances of thechannel associated with the transmission.
 3. The method of claim 1,wherein: the channel comprises a physical downlink shared channel(PDSCH); and the one or more ACK parameters are determined for eachinstance of a control channel associated with each instance of the PDSCHin the transmission such that an ACK is sent on a same uplink subframe.4. The method of claim 3, wherein the control channel comprises amachine type communication physical downlink control channel (MPDCCH).5. The method of claim 1, wherein the size of the transmission indicateswhether the channel has been transmitted in a last instance of the oneor more instances in the transmission.
 6. The method of claim 1,wherein, for each instance of the one or more instances of the channelprior to a last instance of the one or more instances of the channel,the size of the transmission is set to a size greater than a number ofthat instance in the one or more instances of the channel.
 7. The methodof claim 6, wherein the size greater than the number of that instance isa maximum number of allowed instances of the one or more instances ofthe channel with uplink ACK on a same subframe.
 8. The method of claim1, wherein the size of the transmission is set to a correct size of thetransmission if the channel has been transmitted in a last instance ofthe one or more instances in the transmission.
 9. A method for wirelesscommunications by a user equipment (UE), comprising: receiving anindication of one or more acknowledgement (ACK) parameters to use foracknowledging a transmission comprising one or more instances of achannel across one or more subframes, wherein the one or more ACKparameters comprise a first ACK parameter that conveys a size of thetransmission and a second ACK parameter that conveys an amount of timefor the UE to delay acknowledging a data transmission in an instance ofthe channel after receiving the data transmission; and acknowledging thetransmission in accordance with the one or more ACK parameters.
 10. Themethod of claim 9, wherein: the amount of time comprises one or moresubframes; and the size of the transmission comprises a number of theone or more instances of the channel associated with the transmission.11. The method of claim 9, wherein: the channel comprises a physicaldownlink shared channel (PDSCH); and the one or more ACK parameters aredetermined for each instance of a control channel associated with eachinstance of the PDSCH in the transmission such that acknowledging thetransmission comprises sending an ACK on a same uplink subframe.
 12. Themethod of claim 11, wherein the control channel comprises a machine typecommunication physical downlink control channel (MPDCCH).
 13. The methodof claim 11, further comprising: determining a first size of thetransmission based at least in part on the one or more ACK parameters;and determining a second size of the transmission based at least in parton a number of instances of the control channel detected that indicatethe same uplink subframe.
 14. The method of claim 13, wherein the firstsize of the transmission is determined based on the one or more ACKparameters in a last received instance of the one or more instances ofthe control channel of the transmission.
 15. The method of claim 14,wherein acknowledging the transmission comprises sending an ACK in theuplink subframe if the first size is equal to the second size and eachinstance of the PDSCH associated with the uplink subframe is decodedcorrectly.
 16. The method of claim 14, wherein acknowledging thetransmission comprises sending a negative ACK (NACK) in the uplinksubframe if the first size is not equal to the second size or if anyinstance of the PDSCH associated with the uplink subframe is decodedincorrectly.
 17. The method of claim 9, further comprising determiningwhether the channel has been transmitted in a last instance of the oneor more instances in the transmission based in part on the size of thetransmission.
 18. The method of claim 17, wherein the determination isthat the channel has not been transmitted in the last instance of theone or more instances in the transmission if the size of thetransmission is set to a size greater than a number of instances of thechannel received by the UE.
 19. The method of claim 18, wherein the sizegreater than the number of instances of the channel received by the UEis a maximum number of allowed instances of the one or more instances ofthe channel with uplink ACK on a same subframe.
 20. The method of claim17, wherein the determination is that the channel has been transmittedin the last instance of the one or more instances in the transmission ifthe size of the transmission is equal to a number of instances of thechannel received by the UE.
 21. An apparatus for wireless communication,comprising: at least one processor configured to: determine one or moreacknowledgment (ACK) parameters to be used for acknowledging atransmission comprising one or more instances of a channel across one ormore subframes; and signal an indication of the one or more ACKparameters to a user equipment (UE), wherein the one or more ACKparameters comprise a first ACK parameter that conveys a size of thetransmission and a second ACK parameter that conveys an amount of timefor the UE to delay acknowledging a data transmission in an instance ofthe channel after receiving the data transmission; and a memory coupledto the at least one processor.
 22. The apparatus of claim 21, wherein:the amount of time comprises one or more subframes; and the size of thetransmission comprises a number of the one or more instances of thechannel associated with the transmission.
 23. The apparatus of claim 21,wherein: the channel comprises a physical downlink shared channel(PDSCH); and the one or more ACK parameters are determined for eachinstance of a control channel associated with each instance of the PDSCHin the transmission such that an ACK is sent on a same uplink subframe.24. The apparatus of claim 21, wherein, for each instance of the one ormore instances of the channel prior to a last instance of the one ormore instances of the channel, the size of the transmission is set to asize greater than a number of that instance in the one or more instancesof the channel.
 25. The apparatus of claim 21, wherein the size of thetransmission is set to a correct size of the transmission if the channelhas been transmitted in a last instance of the one or more instances inthe transmission.
 26. An apparatus for wireless communication,comprising: at least one processor configured to: receive an indicationof one or more acknowledgement (ACK) parameters to use for acknowledginga transmission comprising one or more instances of a channel across oneor more subframes, wherein the one or more ACK parameters comprise afirst ACK parameter that conveys a size of the transmission and a secondACK parameter that conveys an amount of time for the apparatus to delayacknowledging a data transmission in an instance of the channel afterreceiving the data transmission; and acknowledge the transmission inaccordance with the one or more ACK parameters; and a memory coupled tothe at least one processor.
 27. The apparatus of claim 26, wherein: theamount of time comprises one or more subframes; and the size of thetransmission comprises a number of the one or more instances of thechannel associated with the transmission.
 28. The apparatus of claim 26,wherein: the channel comprises a physical downlink shared channel(PDSCH); and the one or more ACK parameters are determined for eachinstance of a control channel associated with each instance of the PDSCHin the transmission such that acknowledging the transmission comprisessending an ACK on a same uplink subframe.
 29. The apparatus of claim 28,wherein: the at least one processor is further configured to: determinea first size of the transmission based at least in part on the one ormore ACK parameters, wherein the first size of the transmission isdetermined based on the one or more ACK parameters in a last receivedinstance of the one or more instances of the control channel of thetransmission; and determine a second size of the transmission based atleast in part on a number of instances of the control channel detectedthat indicate the same uplink subframe.
 30. The apparatus of claim 29,wherein the at least one processor is configured to acknowledge thetransmission by sending an ACK in the uplink subframe if the first sizeis equal to the second size and each instance of the PDSCH associatedwith the uplink subframe is decoded correctly.